Polar Bear Behavior in Response to Climate Change

Although the Arctic has experienced previous periods of warmer climate, the rate of sea ice loss in recent decades is likely faster than polar bears have ever experienced. The rapidly changing climate means that any response in polar bear behavior is unlikely to be driven by microevolution, but rather it will depend on behavioral plasticity. Fortunately, studies indicate high behavioral plasticity in polar bears despite their marked specialization as a marine predator. Although seals are their primary prey, polar bears feed opportunistically on a variety of marine and terrestrial prey and vegetation. Recently, the greatest change in their feeding behavior has resulted from spending more time on land as seasonal sea ice recedes. Additionally, polar bears will encounter new prey as some temperate species extend their ranges northward. Changes in polar bear movements and habitat associations because of climate change vary among subpopulations. In several areas, the loss of sea ice has altered migration routes, required long-distance swimming between hunting and denning areas, and resulted in some denning areas becoming inaccessible. Because polar bears do not occur in regions without sea ice for a significant part of the year, a diet of seals may not be fully replaceable with alternative terrestrial food, which poses a serious conservation concern.